Cruise to the Incipient Rift
Emily Klein 'Mows' the East Pacific to Reveal Secrets of
Magma p.3
Researchers have been trying to determine how magma compositions
may vary under that 100 kilometer mixing zone, but they “couldn’t
get their hands on it,” she acknowledged. That’s
because by the time the lava emerges on the East Pacific Rise,
its chemistry has evolved from all the mixing and moving the
magma underwent on the way.
The chemical clues Klein got from her 1999 samples suggested
that the Incipient Rift could help resolve this uncertainty.
She proposed to the NSF that, since the IR slices across the
East Pacific Rise’s huge underground magma reservoir,
the “little melts” it emits would provide lava
samples representing various stages of magma movement and
evolution.
“It’s like tapping a rubber tree,” she
said. “The point of this study is, perhaps for the first
time ever, to be able to provide information on the composition
of melt in this wide and deep area that we can never get our
hands on.”
The RV Melville left San Diego on Aug. 5. Its passage
was mostly smooth through “hurricane alley,” the
area of the eastern Pacific where hurricanes can form this
time of year. That was a great relief to Elizabeth (Betsy)
Williams, a second-year Duke graduate student in geology who
worried about getting seasick.
Before Williams left land, she “battle tested”
motion sickness medications by ordering her boyfriend to “drive
me around, swerving all over the road, with me reading and
my face down, and no air conditioning.” She turned 30
on her third day out from the dock, and happily celebrated
with a helping of cake.
Motion issues aside, this voyage was a rite of passage for
Williams. After majoring in English at Haverford College she
had spent seven years in the science and mathematics textbook
publishing industry before taking up geology at Duke. “I
always had this nagging thought in the back of my mind that
I should be doing science,” she said. “So here
I am.”
While this was William’s first at-sea experience, the
trip will provide a doctoral dissertation for fourth-year
graduate student and ocean veteran Heather Hanna, who studies
geochemistry under Klein. “There’s been so little
work on this that it should be a very interesting project,”
she said.
Hanna previously went to the middle of the Atlantic Ocean
as part of a multi-university expedition called MARVEL that
ended up discovering “The Lost City,” a new and
unique geothermal vent field. “I learned so much on
the MARVEL cruise, and I really enjoyed working on the ship,”
she added. “I love being at sea.”
Joining Williams and Hanna at the Incipient Rift was another
graduate student, Meagen Pollock. Also aboard were Mark Rudnicki,
a Duke research scientist in marine geochemistry, and three
Duke undergraduates: Carrie Donnelly, Ryan Cheney and Jenny
McGuire.
They joined an additional contingent of scientists and graduate
students from Woods Hole Oceanographic Institution (WHOI)
in Massachusetts, which supervised the photographic and geomagnetic
observations that backed up Klein’s geochemical investigations.
The mission was unusually heavy on female help, whose job
descriptions would include plenty of heavy lifting. “All
the same 5 foot 2,” exclaimed Williams.“But, heck,
if the men can do it so can we, right?”
As Duke and WHOI students documented from the ship on a Nicholas
School Web site, www.nicholas.duke.edu/
IncipientRift/, expedition researchers began using a shipboard
sonar device called SeaBeam to map the ocean floor topography
(scientists call that “bathymetry”) while they
were still hundreds of nautical miles from the IR.
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